Connect smartphone to the car's infotainment system.
No need for CD or satellite radio subscription.
Stream stuff over the smartphone's Internet connection as long as cell signal is good.
Otherwise stream pre-downloaded stuff from the smartphone.
I stream a lot of audiobook-like programs on YouTube while in the car; for good listening experience, manually select a very low video resolution (saves data, reduce chances of having to wait for buffering because you "waste" less bandwidth on video, which you won't be watching anyway because you're streaming an audiobook-like program).
